In many industries there exists a need to obtain a sample of liquid, gaseous or dry material for quality control purposes, or the like. Often times the material is being transported via tubing, pipe, conduit or other enclosed conveying means. A problem arises in that the representative sample of material must be retrieved from the conveying pipe without impeding the flow of the bulk of the material.
In the oil and gas industry, casing is cemented into wells using different blends of cement for different applications. To achieve the proper blend, different ingredients such as cement, sodium chloride and silica are often conveyed under positive (pressures above atmospheric pressure) via pipes or tubes from a bulk storage tank to a blending unit. Therefore, it is highly desirable to have a device which can accurately and economically take a sample of material at the blending unit of the bulk plant so that the composition of cement actually used at the job site can be compared with the samples taken. Further, the blended cement mixture may not be totally homogeneous in nature, therefore it is also desirable to have a material sampling device which can take a crossection of the material to be sampled.
Several devices are currently known which can obtain material samples, for example, U.S. Pat. No. 4,082,004 to Weber et al shows a cross cut sampler which can take a cross sectional sample of material from a housing connected within a conveying tube. The material sample is then conveyed through a hose to a sample container. This devices uses an externally connected air cylinder to insert and retract the sample head into, and out of the housing. Further, a closure is used which physically abuts the front face of the sample head, while in the retracted position.
U.S. Pat. No. 4,120,203 to Clements et al shows a crosscut sampler for pneumatic conveying systems. A sample head is positioned alongside a conveying pipe and moved perpendicularly across the flow of the conveyed material by an external air cylinder.
Further, U.S. Pat. No. 3,659,461 to Thompson shows a plunger with an inclined baffle attached to the rod of a hydraulic cylinder. The plunger is insertable into a product supply line upon actuation of the hydraulic cylinder. Each of the aforementioned patents utilizes an air or hydraulic cylinder externally connected to a sampling head, which is movable through the conveyed material. The present invention utilizes a cylinder with a piston which is of a hollow construction, wherein the piston is used to convey the material sample from the sampling head to a sample storage area. Therefore, the present invention, by incorporating the cylinder into the sample conveying path, provides a more efficient, simple and compact sampling device than disclosed in any of the aforementioned prior art devices.